Postal Service through the years

The U.S. Postal Service said it will delay its plan to cut mail delivery to five days, saying "restrictive language" in Congress' temporary government funding resolution prohibits the new schedule. The plan was to start Aug. 5. The Postal Service said it will delay the plan "until legislation is passed that provides the Postal Service with the authority to implement a financially appropriate and responsible delivery schedule."

Check out landmark moments in U.S. Postal Service history.

1775: The office that would later become the United States Post Office Department is established by the Second Continental Congress, with the first postmaster general, Benjamin Franklin, taking office.

1825: The dead letter office is established to hold "undeliverable" mail like the stacks of tires seen in this photo from 1925.

1847: The first U.S. postage stamps are issued, featuring Franklin and the country's first president, George Washington.

1850: Henry "Box" Brown mails himself to freedom in a three-foot box from Richmond, Va., to the Anti-Slavery office in Philadelphia. The delivery took 26 hours.

1860: The Pony Express began as a way to deliver mail across the Great Plains and through the Rocky Mountains.

1896: Free rural mail delivery began.

1913: Parcel post delivery begins with the advent of the new auto truck.

1918: Scheduled airmail service begins. The first efforts to deliver mail by air in the U.S. dated back to 1859, when a pilot tried unsuccessfully to carry mail via air balloon from Indiana to New York.

1950: Residential mail deliveries are reduced to one a day.

1959: The Postal Service experimented with "missile mail," teaming up with the U.S. Navy sub The U.S.S. Barbero to fire missiles containing postal containers instead of ordinance. The cost and numerous failures doomed the program to failure.

1963: Non-mandatory ZIP codes are announced for the entire country, and two-letter state abbreviations are introduced.

1970: Express Mail begins experimentally.

1992: Self-adhesive stamps are introduced nationwide. They were first tested in 1974.

1994: The Postal Service launches its public Internet site.

2010: Budget cuts and technological advances like email and Facebook force the Postal Service to close thousands of post offices nationwide.

2012: In the past year, the service cut hours at thousands of post offices. It also merged some of its plants, and twice defaulted on payments totaling $11 billion. The agency reported a loss of $16 billion.